Questions & Answers about Čime se osvježavaš kad je vani tako toplo?
Čime means with what? or by means of what? It is the instrumental singular form of što (what).
So the sentence is literally asking something like:
With what do you refresh/cool yourself when it's so warm outside?
Croatian often uses the instrumental case after the implied idea of using something. That is why you get čime, not što.
Se is the reflexive particle. It shows that the action is directed back to the subject:
- osvježavati = to refresh
- osvježavati se = to refresh oneself / to cool down
In English, we usually do not say refresh yourself every time, but Croatian often uses this reflexive form naturally.
So:
- osvježavaš alone would sound incomplete or would suggest you are refreshing something else
- se osvježavaš means you are refreshing yourself